GS4 battery life is superior to HTC One. HTC One CAN get bettery battery life if you use it constantly. If on heavy use I get the same battery life with each phone. This is about 10-12 hours. During moderate use, the GS4 just blows the HTC one away due to insane standby. The HTC would do 15-17 hours, and the GS4 can do 35 hours.
Heavy use = 4-5 hours screen time, LTE, awake pretty much all the time.
Moderate use = 2-3 hours screen on time, LTE on. This is like 90% of the time I'm using it.
I greenify everything that is not absolutely necessary. The only thing I don't greenify is phone, sms, exchange serivces, Google services framework. overnight, with mobile data off, I would lose .5%/hour with the HTC one. With the GS4 I lose .25%/hour. That adds up over time. Over 24 hours, that's like 12 hours of extra standby and about another hours worth of screen time.
However, for about 90% of usage, it's not gonna matter since you'll plug both phones in when you go to sleep. If you're doing gaming or something on the HTC for long periods, just make sure you have a charger handy.